Characterising the S( 1 D) atoms formed by exciting D 2 S molecules via the intense Rydberg resonances at wavelengths ~139.1 nm and ~129.1 nm

We report high-resolution velocity map imaging studies of the S( 1 D) atoms formed following excitation on two intense absorption bands of gas phase D 2 S molecules, centred at wavelengths ~139.1 and ~129.1 nm. DS-D bond fission is the dominant fragmentation pathway at these wavelengths, yielding SD fragments in both the ground (X) and excited (A) electronic states.Most S( 1 D) atoms arising via the rival S atom elimination channel when exciting at ~139.1 nm are formed with D 2 partners, in a wide range of rovibrational levels. The partially resolved structure in the total translational energy, P(E T ), distributions derived from the S( 1 D) atom images implies two dynamical routes to S( 1 D) + D 2 products following non-adiabatic coupling from the photo-excited Rydberg state to the dissociative 2 1 A potential energy surface (PES).Similar D 2 products are evident in the P(E T ) spectra derived from analysis of S( 1 D) images from D 2 S photolysis at ~129.1 nm, but their contribution is overshadowed by a feature attributable to three-body dissociation to S( 1 D) + 2D fragments. These atomic products are deemed to arise via a natural extension of the dynamics responsible for the previously observed highly rotationally excited SD(A) fragments arising via the rival S-D bond fission pathway: asymmetric bond extension together with dramatic interbond angle opening driven by torques generated after coupling to the highly anisotropic 2 1 A PES, leading to centripetally-driven break-up.